Power-hacksaw.



1:. s. BRADFORD, JR 11 M. OLSON. POWER HAOKBAW.

APPLICATION TILED SEPT. 24, 1909.

988,624, Patented Apr. 4, 1911.

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E. S. BRADFORD, JR. & M. OLSON.

rowan HAOKSAW.

APPLICATION FILED SEPT. 24, 1909.

988,624. Patented Apr. 4, 1911.

3 SHEETS-BEEET 2.

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E. s. BRADFORD, JR. O M. OLSON.

POWER HAOKSAW.

APPLIOATION FILED SEPT. 24', 1909.

Patented Apr. 4, 1911.

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UNITED STATES DATEN T OFFICE.

EDWARD S. BRADFORD, JR., F CHICOPEE, MASSACHUSETTS, AND MAURITZ OLSON,OF BRIDGEPORT, CONNECTICUT; SAID OLSON ASSIGNOR TO SAID BRADFORD.

POWER-HACKSAW.

Specification of Letters Patent.

Patented Apr. +1, 1911.

Application filed September 24, 1909. Serial No. 519,371.

To all whom it may concern:

Be it known that we, (1) EDWARD S. BRAD- roRD, Jr., and (2) NIAURITZOLsoN, citizens of the United States, residing at (1) Chicopee, countyof Hampden, State of Massachusetts, and (2) Bridgeport, county ofFairfield, State of Connecticut, have invented an Improvement inPower-Hacksaws of which the following is a specification.

This invention relates to certain improvements in power hacksaws.

The invention has for its object the production of improved means forautomatically adjusting the stroke of the saw to conform to the size andcharacter of the object being operated upon.

A further object of the invention is to provide a power hack-saw havingmeans for automatically stopping the saw when the work is cut through orat any predetermined time.

WVith these and other objects in View the invention consists in certainconstructions and in certain parts, improvements and combinations whichwill be hereinafter clescribed and then specifically pointed out in theclaims hereunto appended.

In the accompanying drawings forming a part of this specification, inwhich like characters of reference indicate the same parts, Figure 1 isa plan View of the machine complete; Fig. 2 a side elevation thereof;Fig. 3 a detail view of a cover plate for the slide; Fig. 4 an end Viewas seen from the right in Fig. 2; Fig. 5 a detail elevation on an enlarged scale partly broken away, corresponding with Fig. 2 and showing achanged position of the blade lifting mechanism; Fig. 6 a detail view ofthe clutch operating mechanism; Fig. 7 a detail view of the pinionshaft; Fig. 8 a detail view of the sleeve which carries the gear wheeland eccentric; Fig. 9 a detail plan view ofthe stroke adjustingmechanism; Fig. 10 an elevation as seen from the left in Fig. 9 with thecover plate removed; Fig. 11 a detail elevation as seen from the rightin Fig. 9; Fig. 12 a detail rear elevation corresponding with Fig. 5;Fig. 13 a section on the line 13-13 in Fig. 12; Fig. 14: a section onthe line 1 l1 l in Fig. 9; Fig. 15 a section on the line 15-15 in Fig.9; Fig. 16 a detail plan View of the clutch mechanism; and Fig. 17 is adetail rear elevation of the saw operating lever.

As shown in the drawings, power is applied to drive the machine by meansof a belt (not shown) passing over a pulley 20 on a shaft 21 j ournaledin a bearing (36 upon the framework, which is indicated as a whole by27. Shaft 21 carries a pinion 22 which meshes with a gear wheel 23carried by a sleeve 24 which is mounted on a shaft 25 and journaled in abearing 26 upon the framework. The special form of driving mechanism isof course immaterial as any rotating member may be used in lieu of agear wheel. Sleeve 24. also carries a cam 28 which lies in the innerface of the gear wheel and may be formed integral therewith, (see Fig.12 in connection with Fig. 5). Upon the outer face of gear wheel 23 is aslide 29 which is adapted to reciprocate in wa s30 and is provided witha pin 31. The slide is provided with an internal rack 32 which mesheswith a pinion 33 carried by shaft 25 and is retained in place by a coverplate 34 having a slot 35 through which pin 31 projccts. The sawcomprises a blade 36 carried by a frame 37 which slides upon a bar 38-.Reciprocatory movement is imparted to the saw from gear wheel 23 bymeans of an operating lever 39 pivoted on the framework as at 40 andconnected to the saw frame by means of a link all. Connection with thegear wheel is made by means of a sliding block 42 lying in a groove 43in lever 39 and provided with a hole which receives pin 31 (see Fig. 17,in connection with Fig. 2).

The work to be operated upon is held by j aws 441 and 45 which are movedtoward and from each other to grip or release the work by means of aright and left threaded screw 46 which is mounted to rotate on theframework, one of the bearings being indicated by 47, and is providedwith a pivoted operating handle 48.

The length of the stroke of the saw is controlled from jaw 45 by meansof a link 49 which is pivoted to the jaw as at 50 and to one arm of abell crank lever 51 pivoted to the framework as at 62 (see Fig. 9 inconnection with Fig. 1). The other arm of the bell crank lever carries aroller 52 which travels in a circumferential groove 53 in an oppositethereto with a spiral slot 57 which is engaged by aipin or block58 :(inthe present instance a pin) which projects from an enlargement 59 at theouter end of shaft 25.

This enlargement is of uniform diameter with sleeve 24 and lies withinsleeve 54. As

already stated, sleeve 24 is journa'led in at bearing 26 on theframework and the sleeve is retained against longitudinal movement bythe hub 60 of gear wheel 23 and by a collar "61 on the sleeve whichbears against the opposite "end of the bearing.

The automatic adjustment of the length of the stroke to correspondwiththe spacing 'of'thejaws,that is, with the size of the piece of workto be operated upon, is'effected by the mechanism just'described.Movement of the 'jaws ineither direction by lneansof link '49 will swingthe bell crank lever, which in partial rotation 'of sleeve 54: istransmitted tosha ft 25 and the 'rotarymovement of said shaft is doubledthrough the engagement of pin or bl0ck'58 which extends from "theenlargement of shaft 25 and engages spiral slot'57 in outer sleeve Shaft25 carries pinion33 and the rotary movement "of this .pini'on throughits engagement with rack 32 on slide'29 reciprocates said slide in the:ways, in the outer face of gear wheel 23, 'iiroving pin'3-1 toward'orfrom the centerof imitation of said gear w'heel. As "the slide is movedin or out pin '81 which engages sliding block 42 in operating lever 39"will be moved toward or from the center of rotation of the gear wheeland will consequently lengthen or'shorten the arc of movement-of theoperating lever which turn through link 41' will correspondinglylengthen or shorten ?the stroke of the saw. It will of course beunderstood thatfthe parts are so proportioned and positioned as toaccurately accomplish this result. In practice the full length of thesaw is operative upon any piece of work. If tthe jaws are "opened widelyto "receive a relatively large piece of s work the stroke of the saw iscorrespondingly shortened.

correspondingly lengthened and the cutting o f the 'ni'etal 'w-illproceed m iichmorer'apidly. The lifting 'ofth'e saw on the return strokeis effected by the mechanism which we will -now describe.

pon whichthe saw frame racis If the aws are moved closer together togrip and ?hold 'a relatively "small piece of work, the stroke of the sawis i ca-tes is rigidly secured to a disk 63 which is itself secured to ashaft "64: journaled in a bearing 65 upon'the framework. The inner faceof this disk is provided with a recess 67 which receives an outwardlyacting spring clamping ring 68 which bears against the wall of therecess and is shown retained in place therein by the heads of bolts 69.The ends of th'e'spring clamping ring overlap, the inner end beingspecifically indicated by 68 ai'id'the'out'erend by 68 70 denotes an armwhich is pivoted to each of the overlapping ends of the spring clampingring-as at .71 and 72. At the lower end of this arm i'sa roller 73 whichbears upon the face ofcam 28 carried by sleeve 2d and lying within theinner face of gear wheel 23 '(see Fig. 12 in connection with A spring 74connected to "arm '70 and to the framework acts to retain the rollerclosely in engagement with the face of the cam.

The "operation of raising the saw for the return stroke "is as follows:The parts are so timed that at the end of the forward stroke of the saw,roller 7 3 will ride" up on the higli portion of cam 28, the effect ofwhich is to swing'arm ,70 and owing "to the Wall of the recess in whichit lies locking the ring to the disk-and oscillating the'disk whichswings arm 38 and with it the saw upward and retains it in the raisedpos i'tion during *the return stroke, at the "end o f w'hich the rollerwill ride down onto the low portion of the cam releasing the grip of thespring clamping ring *on {the disk and permitting said disk, arm 38 andthe saw to drop to their normal position an ins tan flbefore thecommencement of the neixt forward or operative stroke. The distance towhich the saw israised during the return stroke is determined 'by"adjustment of the tension of the-clamping ring which is effectedby-means of a screw 7 5 mounted in the framework and bearing againsttheupper ;end offai'm 70 {(see Fig. 12 in connection with Fig. 5). It will"be obvious that by ,tightening up screw 75 the of "ring :68 upon thewall or the retaining recess will be reduced and consequently lessoscillation will be imparted distance between the-pivotal points of saidfarm to *the'spring cla mplng r ng to ex and said ringou-tward and causeit to grip the to the disk by t'he'inoveinent of arm mend bar 38 uponwhich the saw frame reciproca tes will not' be swung'ashi'gh. Slightloos- *eningof screw 75 will increase the of the spring clam-ping ringupon the wall of the recess and will "consequently increase the"oscillation of the disk and the lift of the saw carrying bar. a

The amount ofp'res'sure of the saw upon t'h e work is determined by theadjustment of'a weight 7 (ion a ca1ryingrol*77',one end of which issecured to the forward end of bar 38 and the other to the rear end ofshaft 64. The rod in practice is made flat and the weight is shown asprovided with a slot through which the rod passes, said slot beinglocated at one side of the center of the welght so as to permit thelatter to be moved clear to the forward end of the rod if required toincrease the pressure upon the saw. The downward movement of the sawafter a piece of work has been cut through is limited by the engagementof a stop lug 78 011 disk 63 with a fixed portion of the framework, asclearly shown in Fig. 13. Should it be required to hold the saw raisedout of operative position when not in use bar 38 is swung upward and apin 79 upon the inner side of said bar is engaged with a notch 80 in aholding bar 81 which is pivoted to the framework, and, when the saw isnot held in the raised position, rests against the pin as indicated inFigs. 1 and 2. I

The operation of the saw is automatically stopped when the work is cutthrough or at any predetermined time by mechanism which we will nowdescribe.

Belt pulley 20 is loose on shaft 21 and the hub 82 of said pulley iselongated and is provided with a clutch member 83 and with acircumferential groove 84;. Shaft 21 carries a fixed clutch member 85which is adapted to be engaged by clutch member 83 to communicate themotion of the belt pulley to shaft 21 and through the mechanism alreadydescribed to impart reciprocatory motion to the saw.

86 denotes a controlling shaft which is journaled in the framework andis provided with a hub 87 having a hand piece 88 and carrying a cam 89,shown in the present instance as a skeleton cam. This cam engages anotch 90 in a clutch lever 91 which is pivoted to the framework as at 92and is provided with a pin or roller (see dotted lines Fig. 16) whichengages groove 84 in hub 82 of the belt pulley. At the ends of the camare stops 93 which limit the oscillation of the cam and the shaft andprevent the cam from becoming disengaged from the clutch lever. At theopposite end of shaft 86 from the cam and handle is a stop pin 94 whichis adapted to slide freely in a hole in the shaft and is locked at anydesired adjustment by means of a set screw 95. WVhen the controllingshaft is at its normal position the hand piece extends upwardapproximately vertically and the stop pin lies at an angle to the handpiece, the upper end of the pin being inclined away from the saw andtoward the driving mechanism. The back of the upper end of the stop pinis rounded and the face of the upper end is provided with a slightrecess, as at 96.

97 denotes a pawl which is pivoted to link 41 as at 98 and which restsupon a boss or projection 99 on the link. The forward end of the pawlextends downward and outward into position to engage in 94. The time atwhich the machine wil be stopped is determined by the adjustment of thestop pin.

In use, the saw will drop downward as it cuts into the work. If theengaging end of the pawl drops below the stop p111 after passing it, thepawl will be lifted by the rounded upper end of the pin and will passover it freely, but at the next forward stroke of the saw the pawl willengage with the pin, the recess being provided to insure engagementtherewith, and the pin will be swung forward oscillating shaft 86 andthe clutch lever through the engagement of the cam therewith, movin thebelt pulley outward on shaft 21 and isengaging the clutch membersthereby stopping the rotation of shaft 21 and the driving mechanism.Should it be required to stop the saw at any time during its operation,this may be effected by oscillating shaft 86, the cam and the clutchlever by means of the hand piece. After the machine is stopped, bar 38carrying the saw may be swung upward and locked in the raised positionby means of bar 81, as already explained.

100 denotes a sliding gage the free end of which is curved to adapt itto be swung to a position in alinement with the center of a piece ofwork gripped by the jaws. The shank of the gage slides in half socketsin the under side of the framework and in a block 101 and it is lockedat any required adjustment by a clampin screw 102. This gage is usedwhen a number of pieces are to be cut to the same length. Vhen not inuse the clamping screw is turned slightly backward which permits thegage to drop downward out of the way.

Having thus described our invention, we claim 1. An improvement in hacksaws comprising work holding jaws, a rotatable member, a radiallyadjustable slide carried thereby, a saw, means for reciprocating saidsaw, said means being operatively connected with said slide, and meansconnected with one of said jaws for adjusting said slide.

2. An improvement in hack saws comprising a crank wheel, a radiallyadjustable crank pin carried thereby, a saw, means operated by saidcrank pin. for reciprocating said saw, work holding jaws, and meansconnected with one of said jaws and said crank pin for adjusting theposition of the crank pin.

3. An improvement in hack saws comprising a crank wheel provided with aradially adjustable crank pin, a sleeve on which said crank wheel ismounted, a saw, means operated by said crank wheel for reciprocatingsaid saw, work holding jaws, a shaft mounted in said sleeve andconnected with one of

